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      1 // Copyright 2012 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #ifndef SYNC_INTERNAL_API_PUBLIC_WRITE_TRANSACTION_H_
      6 #define SYNC_INTERNAL_API_PUBLIC_WRITE_TRANSACTION_H_
      7 
      8 #include "base/basictypes.h"
      9 #include "base/compiler_specific.h"
     10 #include "sync/base/sync_export.h"
     11 #include "sync/internal_api/public/base_transaction.h"
     12 
     13 namespace tracked_objects {
     14 class Location;
     15 }  // namespace tracked_objects
     16 
     17 namespace syncer {
     18 
     19 namespace syncable {
     20 class BaseTransaction;
     21 class WriteTransaction;
     22 }  // namespace syncable
     23 
     24 // Sync API's WriteTransaction is a read/write BaseTransaction.  It wraps
     25 // a syncable::WriteTransaction.
     26 //
     27 // NOTE: Only a single model type can be mutated for a given
     28 // WriteTransaction.
     29 class SYNC_EXPORT WriteTransaction : public BaseTransaction {
     30  public:
     31   // Start a new read/write transaction.
     32   WriteTransaction(const tracked_objects::Location& from_here,
     33                    UserShare* share);
     34   // |transaction_version| stores updated model and nodes version if model
     35   // is changed by the transaction, or syncer::syncable::kInvalidTransaction
     36   // if not after transaction is closed. This constructor is used for model
     37   // types that support embassy data.
     38   WriteTransaction(const tracked_objects::Location& from_here,
     39                    UserShare* share, int64* transaction_version);
     40   virtual ~WriteTransaction();
     41 
     42   // Provide access to the syncable transaction from the API WriteNode.
     43   virtual syncable::BaseTransaction* GetWrappedTrans() const OVERRIDE;
     44   syncable::WriteTransaction* GetWrappedWriteTrans() { return transaction_; }
     45 
     46  protected:
     47   WriteTransaction() {}
     48 
     49   void SetTransaction(syncable::WriteTransaction* trans) {
     50     transaction_ = trans;
     51   }
     52 
     53  private:
     54   void* operator new(size_t size);  // Transaction is meant for stack use only.
     55 
     56   // The underlying syncable object which this class wraps.
     57   syncable::WriteTransaction* transaction_;
     58 
     59   DISALLOW_COPY_AND_ASSIGN(WriteTransaction);
     60 };
     61 
     62 }  // namespace syncer
     63 
     64 #endif  // SYNC_INTERNAL_API_PUBLIC_WRITE_TRANSACTION_H_
     65